In conducting advocacy, non-governmental organisations (NGOs) often repeatedly lobby targets that have already made reforms, while also ignoring some serious, unreformed offenders. Drawing on recent literature on the economic influences on NGO activity, this article proposes a new model of target selection that explains such behaviour. In the model, NGOs select their targets in order to maximise the level of reform achieved with their available resources. Initial target selection is based on limited information. Target response to initial advocacy reveals whether the target is ‘soft’ (low cost to benefit ratio) or ‘hard’ (high cost to benefit ratio). NGOs employ this information to maximise the benefits of their resources, abandoning targets deemed too costly to change and repeatedly lobbying those deemed likely to make changes at little cost. We demonstrate the applicability of the model using two cases from the Jubilee debt relief movement. We then explore the implications of our findings for NGOs’ performance as watchdogs.